I am relatively new to the Nikon but I had some unpleasant experiences that are making me think about trying Canon. I'll list:

1) The issue of oil / dust on the sensor. It's pretty clear to anyone who bought the D600 that will have to live with it forever. I do not want a camera that requires much maintenance.

2) I had problems with SD card slot 2 on my D600. It just was not recognizing the card until I played with a key there and somehow allow the contact.

3) I bought a used 24-70mm. I know that was a mistake. But served to find out how many problems has this essential Nikkor lens: Zoom ring rubber loosing , "stiff" zoom and I'm still discovering more.

4) There are a lot of people that complain abot the colors Nikon cameras produces. I always thought the colors from Canon are more vivid, but I thought it was my mind. But recently I saw a lot of people drawing attention to it. So it's not just me.

It is clear to me that Nikon has a serious problem with the QC.If it is clear to me that the 5D markIII gives me better IQ, AF, Colors, HIGH ISO, Radio Flashes etc, today for $ 800 more, I think, for FF beginners like me it is worth investing in Canon.